Amphiphilic oligomer-based micelles as cisplatin nanocarriers for cancer therapy

Polymeric micelles (similar to 10 nm) have been prepared from the amphiphilic oligomer comprising oligomeric polystyrene as the hydrophobic inner core and half of EDTA (-N(CH2COOH)(2)) as the hydrophilic outermost shell. After chelating cisplatin with -N(CH2COOH)(2) in water, polymeric micelles containing Pt on the spherical surface have been easily obtained. Since the chelate group is introduced into the amphiphilic oligomer as the terminal group by a RAFT agent, the chelation of cisplatin with PS(COOH)(2) is almost stoichiometric. The drug carrier based on PS(COOH)(2) showed a high loading efficiency (>70%) towards cisplatin. The release of the therapeutic Pt from the cisplatin-loaded composites (PS(COOH)(2)-Pt) triggered under weak acidic conditions resulted in good Pt-release and accumulation in tumor cells. Both in vitro and in vivo, the chelated cisplatin inhibited Sk-Br3 cancer more effectively than the intact cisplatin does. Furthermore, neither PS(COOH)(2) nor PS(COOH)(2)-Pt showed obvious systematic toxicity.